PNNL

Abstract

There are over 50 million gallons of waste in underground tanks at the Hanford site in Washington State which was generated as a byproduct of nuclear materials fabrication for United States strategic defensive purposes. The waste, also known as high-level waste (HLW), is comprised of both radioactive and non-radioactive contaminants. To deal with the tank waste, the United States Department of Energy (DOE) plans to separate out the liquid, or supernatant, and salt-cake portions and treat them as low-activity waste (LAW). The LAW and HLW will be vitrified in separate facilities at the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The LAW will be disposed of at the on-site Integrated Disposal Facility (IDF). The main species of concern in the immobilized low-activity waste (ILAW) include 99Tc, 129I, and U and other non-radioactive contaminants. Ultimately, it must be demonstrated that the contaminants released from the waste form pose minimal risk to humans and the environment. To aid in this demonstration, work is currently being done to expand the understanding of long-term glass waste form behavior, especially with regards to exposure to aqueous environments.